1. Field of the Invention:
The present invention generally relates to a device that can monitor a plurality of parameters and control a plurality of devices relating to the washing of articles and, more particularly, to a monitoring and control apparatus that incorporates a wash process sensor that comprises a microcontroller which is capable of performing measuring, monitoring, calculating and controlling the process of washing articles.
2. Description of the Prior Art:
Many different machines for washing articles are known to those skilled in the art. In addition, numerous dishwashers and clothes washing machines are known which measure parameters relating to the washing process and provide information which is helpful in determining the degree of cleanliness or dirtiness of the articles being washed. One commonly measured parameter relates to the turbidity of the water used in the washing process. By monitoring the degree of turbidity of the wash solution, the satisfactory progression of the process can be determined.
U.S. Pat. No. 5,172,572, which issued to Ono on Dec. 22, 1992, discloses an automatic washing apparatus for washing dirty items in a tank to which washing liquid is supplied. The apparatus is described as comprising a light emitting element for emitting light to the washing liquid which is past through the washing tank. A first light receiving element is provided for receiving a light beam that travels through the washing liquid along the optical axes of the light emitting element. A second light receiving element for receiving scattered light that travels through the washing liquid in directions deviated from the optical axis of the light emitting element is also provided. The washing conditions are controlled in accordance with the quantity of light received by the first light receiving element and the quantity of light received by the second light receiving element.
U.S. Pat. No. 5,291,626, which issued to Molnar et al on Mar. 8, 1994, describes a machine for cleansing articles. The machine can be a dishwasher. It incorporates a device for measuring the turbidity of at least partially transparent liquid. The device includes a sensor for detecting scattered electromagnetic radiation, regardless of polarization, and a sensor for detecting transmitted electromagnetic radiation regardless of polarization.
U.S. patent application Ser. No. 08/246,902, which was filed on May 20, 1994 by Boyer et al and assigned to the Assignee of the present application, discloses a sensor platform for use in machines for washing articles. A plurality of fluid condition sensors are combined together to provide a sensor cluster that senses turbidity, temperature, conductivity and the movement of the ferromagnetic object. The plurality of sensors are attached to a substrate and encapsulated, by an overmolding process, with a light transmissive and fluid impermeable material. The sensor cluster can be disposed at various different locations within a body of fluid and does not require a conduit to direct the fluid to a particular location proximate the sensor. In a preferred embodiment of the present invention, a circuit is provided which monitors the signal strength of first and second light sensitive components to determine turbidity and, in addition, those signal strengths are also used to advantageously determine the most efficient magnitude of current necessary to drive a light source, such as the light emitting diode. By controlling the current to a light emitting diode as a function of the strength of light signal received by first and second light sensitive components, the turbidity sensor can be operated at a more efficient and effective level.
French patent 2,485,576, which was made public on Dec. 31, 1981, discloses a procedure for the adaptation of washing time and of the quantity of rinsing water for a load of laundry in a washing machine. This French patent, which was filed by Hazan et al on Jun. 24, 1980, describes a laundry machine in which electrical signals coming from photodetectors are monitored by a microprocessor with a read-only memory, a random-access memory and a comparative element. A program is stored in the read-only memory of the microprocessor and is used during continuous washing and rinsing or in cycles used by the machine. During the washing or rinsing procedures the active memory stores the value of the signal coming from the photodetectors for a series of instance in time. If the signals exhibit very slight change, the microprocessor interprets this situation as corresponding to the reaching of a limit for the opacity of the washing water or for the degree of purity of the rinsing water. In that case, the comparator sends a signal to stop the washing or rinsing cycle. On the other hand, the washing or rinsing cycles can continue until a limit which is either opacity or the degree of purity of the water is detected.
U.S. Pat. No. 4,257,708, which issued to Fukuda on Mar. 24, 1981, describes an apparatus for measuring the degree of rinsing in an apparatus for washing articles. The apparatus for measuring the degree of rinsing is provided with a source of light, a first phototransistor disposed to receive light emitted by the light source for producing a reference signal, a second phototransistor disposed to receive the light from the light source for producing a measuring signal corresponding to the amount of light received an a calculating circuit for arithmetically operating the reference signal and the measuring signal for producing an output signal corresponding to the relative values of the reference signal and the measuring signal. A first optical path between the light source and the first phototransistor and a second optical path between the light source and the second phototransistor are both disposed in rinsing water and the length of the first optical path is set to be longer than the length of the second optical path.
As will be described in greater detail below, the use of a smart sensor in a machine for washing articles has been found to provide a significant benefit to the washing of articles. In particular, a turbidity sensor can be advantageously used to reduce the quantity of water used in the procedure of washing dishes. By monitoring the degree of turbidity and the rate of change of turbidity of the washing liquid, the timing of the washing and rinsing cycles can be advantageously controlled to reduce both the use of water and, in addition, the use of electricity. Therefore, smart sensors can improve both the efficiency and the effectiveness of the process of washing articles.
In typical applications known to those skilled in the art, sensors are used to measure various parameters relating to the washing of articles by an appliance. The measured parameters are then communicated to a controller which changes the rinsing and washing cycles in conformance with preselected algorithms. Certain disadvantages have been experienced in apparatus of this type. In applications where smart sensors are used to measure the parameters, a microprocessor or microcontroller is typically used as part of the sensor or sensors. However, since the controller typically uses a microcontroller also, the cost of the machine for washing articles is increased as a result of this redundancy in component usage. The cost of the machine is increased in several ways by a system that requires this number of components. Original manufacturing costs are naturally larger. In addition, wiring harnesses are required. Because of the larger number of devices, overall reliability of the total system is reduced. Assembly costs are increased because of the required interconnections. Since the various intelligent components must be able to communicate with each other, some type of communications protocol must also be included as part of the total system. It would therefore be significantly advantageous if a wash process sensor could be provided with the capability of measuring a plurality of parameters and is also the controlling the wash process.